<abstract><title style='display:none'>Abstract</title>The structural integrity of precast concrete structures mainly depends on the connections between the precast structural elements. The purpose of a connection is to transfer loads, restrain movement, and/or to provide stability to a component or an entire structure. Therefore, the design of connections is one of the most important aspects in the design of precast concrete structures. All the connections should be designed according to the valid codes. All precasters have developed connection details over the years that suit their particular production and erection preferences. It is common that the structural engineer shows the internal forces and connection locations, and the manufacturer’s engineering department provides the final design and details of the connections. This paper describes basic types of connections and joints used in precast concrete structures</abstract>

Connections and Joints in Precast Concrete Structures

<abstract><title style='display:none'>ABSTRACT</title><italic>The article introduces the concept and content of facilities management (FM) services. The</italic><italic>paper presents the concept of customer satisfaction and discusses the key factors which</italic><italic>influence the opinions of customers and their satisfaction or dissatisfaction with the</italic><italic>services provided. The article presents two studies: a brief survey of several FM service</italic><italic>providers and a survey of customer satisfaction with FM services in Lithuania. The</italic><italic>conclusions are given at the end of the article.</italic></abstract>

Department of Construction Economics and Property Management Vilnius Gediminas Technical University, Sauletekio ave. 11, LT–10223 Vilnius, Lithuania

Study on Customer Satisfaction with Facilities Management Services in Lithuania

<abstract xml:lang="en"><title style='display:none'>On the use of the Muskingum method for the simulation of flood wave movements</title>The Muskingum method is a hydrological flow routing model with lumped parameters, which describes the transformation of discharge waves in a river bed using two equations. The first one is the continuity equation (conservation of mass) and the second equation is the relationship between the storage, inflow, and outflow of the reach (the discharge storage equation). These equations are applied within a river reach between two cross sections of a river. The parameters of the model can be estimated by several methods. Here the classical graphic method is compared with two new methods where a genetic algorithm and harmony search was used for optimization. The discrete state space formulation of the Muskingum method was applied on the lower Morava reach between Moravský Svätý Ján and Záhorská Ves. The results showed a good degree of accuracy of all three methods, which were assessed by the Nash-Sutcliffe efficiency coefficient.</abstract>

On the use of the Muskingum method for the simulation of flood wave movements

<abstract xml:lang="en"><title style='display:none'>Improvement performance of secondary clarifiers by a computational fluid dynamics model</title>Secondary clarifier is one of the most commonly used unit operations in wastewater treatment plants. It is customarily designed to achieve the separation of solids from biologically treated effluents through the clarification of biological solids and the thickening of sludge. As treatment plants receive increasingly high wastewater flows, conventional sedimentation tanks suffer from overloading problems, which result in poor performance. Modification of inlet baffles through the use of an energy dissipating inlet (EDI) was proposed to enhance the performance in the circular clarifiers at the Al-Dewanyia wastewater treatment plant. A 3-dimensional fully mass conservative clarifier model, based on modern computational fluid dynamics theory, was applied to evaluate the proposed tank modification and to estimate the maximum capacity of the existing and modified clarifiers. A Computational Fluid Dynamics (CFD) model was formulated to describe the tank is performance, and design parameters were obtained based on the experimental results. The study revealed that velocity and (suspended solids) SS is a better parameter than TS (total solids), (Biochemical Oxygen Demand) BOD, (Chemical Oxygen Demand) COD to evaluate the performance of sedimentation tanks and that the removal efficiencies of the suspended solids, biochemical oxygen demand, and chemical oxygen demand were higher in the baffle.</abstract>

Department of civil Engineering, Faculty of civil Engineering, AL-Qadisyia University, Iraq

Department of Sanitary and Environmental Engineering, Faculty of Civil Engineering, Slovak University of Technology, Radlinského 13, 813 68, Bratislava, Slovakia

Improvement performance of secondary clarifiers by a computational fluid dynamics model

<abstract><title style='display:none'>Abstract</title> This study focuses on the soft-storey behavior of RC structures with lead core rubber bearing (LRB) isolation systems under near and far-fault motions. Under near-fault ground motions, seismic isolation devices might perform poorly because of large isolator displacements caused by large velocity and displacement pulses associated with such strong motions. In this study, four different structural models have been designed to study the effect of soft-storey behavior under near-fault and far-fault motions. The seismic analysis for isolated reinforced concrete buildings is carried out using a nonlinear time history analysis method. Inter-story drifts, absolute acceleration, displacement, base shear forces, hysteretic loops and the distribution of plastic hinges are examined as a result of the analysis. These results show that the performance of a base isolated RC structure is more affected by increasing the height of a story under nearfault motion than under far-fault motion.</abstract>

Effect of a Near Fault on the Seismic Response of a Base-Isolated Structure with a Soft Storey

<abstract><title style='display:none'>Abstract</title> The implementation of the Eurocodes in current structural design practice has brought about a new emphasis on the design of earthquake-resistant structures. In some European countries, new earthquake zones have been defined; henceforth, the design requirements of many ongoing projects have changed as well. The choice of the ductility class of steel structures as one of the key design parameters, the consequences of this choice on design procedure, and some applications of the Eurocode 8 design criteria by comparing French and Slovak national practice are discussed, using a practical example of a structure.</abstract>

EGIS Industries, 40, Boulevard de Dunkerque, 13002 Marseille, France

Department of Steel and Timber Structures, Faculty of Civil Engineering, Slovak University of Technology, Radlinského 11, 813 68 Bratislava, Slovakia

Some Remarks on the Choice of Ductility Class for Earthquake-Resistant Steel Structures

<abstract>
<title style='display:none'>Abstract</title>
The transportation network is the most important component of an urban infrastructure. The efficiency of a region’s transportation system can be understood by the effectiveness of its transport network arrangement. The current study employs Geographical Information Systems (GIS) to assess the structure of a transport network in various clusters of the Hyderabad Metropolitan Area (HMA). The study focuses on a thorough assessment of the transport (or) road network structure in terms of various criteria such as connectivity, accessibility, maturity, and development. The study also categorizes each Transport Network Structural Evaluation Criteria (TNSEC) level as “very low, low, medium, high, or very high”. The goal of this research is to create a Road Network Structural Performance Index (RNSPI), which is usually used to measure the efficiency of a study area’s transportation network structure. The study’s findings serve as a foundation for city transportation planners to put efforts in the planning to enhance network facilities in the study region. The study also investigates the utility of Arc GIS software in assessing the structure of an urban transport network.
</abstract>

A Methodology for a Comprehensive Evaluation of an Urban Transport Network Structure Using Geographical Information Systems (GIS)

<abstract>
<title style='display:none'>Abstract</title>
The objective of this study is to assess the impact of incorporating rubber tire waste and brick fillers as a substitute for sand in cement mortar samples. The evaluation includes measurements of the bending strength, dynamic modulus of elasticity, and displacement. The replacement of sand by rubber waste (RW) and brick waste (BW) at 0%, 10%, 20% and 30% for rubber waste and 0%, 2.5%, 5.0%, 7.5%, and 10% for brick waste by volume was experimentally conducted. According to the findings, the introduction of rubber waste leads to a significant reduction in the flexural strength, dynamic modulus of elasticity, and displacement. The brick waste can be considered a suitable filler, which minimizes the negative effect of rubber tires and tends to result in suitable mixtures. The optimal values (10.10% for the RW and 10% for the BW) showed good agreement with the experimental results, with differences of 1.85%, -4.73%, and -4.48% for the displacement, flexural strength, and dynamic elastic modulus, respectively.
</abstract>

Some Properties of a Cementitious Mortar Containing Granulated Rubber Waste and Brick Fillers: An Experimental Study, Mathematical Modeling and Optimization

<abstract>
<title style='display:none'>Abstract</title>
In the paper, we present the results of an analysis of data samples of 282 damaged buildings; the samples include the age of the building, the type of vertical bearing structures, the type of construction of the external walls, the method of the insulation of the walls, the number of floors, the buildings’ functions, and the extent of the damage. The primary objective of the analysis was to evaluate the possibility of using panels of cold-formed thin-walled steel profiles to repair the damaged structures. The results of a study of typical projects of large panel buildings that were constructed in Ukraine and an analysis of the practical experience of repairing these types of buildings after blast actions can also be found. The research tasks are defined for implementing this technology in the process of repairing large panel buildings.
</abstract>

Panels of Cold-Formed Steel Profiles: Possibility of Their Use to Repair War-Damaged Large-Panel Buildings

<abstract>
<title style='display:none'>Abstract</title>
Facilities for children and young people should be established in a healthy environment that is protected from external health-damaging factors, such as noise, air pollution, and negative educational influences. A school building should also be a safe and healthy environment for pupils and students, as legally required. However, although some school buildings have been renovated, most were constructed in the last century, and their indoor microclimate remains unsatisfactory. Schools must maintain optimal thermal and humidity conditions to ensure the healthy development of children and their ability to function properly in a classroom. While natural ventilation through opening windows is a good practice, it may not always guarantee sufficient air exchange, especially for schools located in busy traffic areas. This paper presents experimental measurements and a comparison between two primary schools in Bratislava, which describes the current thermal and humidity conditions in the indoor environment of both schools. Experimental measurements were carried out on five school days in each primary school to determine the thermal-humidity conditions and indoor air quality, depending on the concentrations of carbon dioxide.
</abstract>

Experimental Measurements in Schools with Natural Ventilation

<abstract>
<title style='display:none'>Abstract</title>
Ensuring the sufficient residual resistance of glass structures after the failure of one glass ply to the failure of all the glass plies is an integral part of the design of glass structures. This paper presents an experimental study of bolted connections in laminated glass during three stages of a glass specimen: an intact glass specimen, a specimen with one ply of glass broken, and a specimen with both plies of glass broken. The effect of the type of glass was observed. The experiment proved that laminated glass made from thermally-toughened glass with bolted connections in its unfractured state has significantly higher resistance than laminated glass made from annealed glass. In a state of both plies of glass broken, the specimens made from annealed glass showed a higher residual resistance than specimens made from thermally toughened glass. The performance at this stage was also influenced by the temperature and loading speed. The expected strength of the glass was calculated on the basis of numerical models.
</abstract>

Experimental Analysis of the Post-Fracture Behaviour of Laminated Glass With Bolted Connections

<abstract>
<title style='display:none'>Abstract</title>
The interval of time after pouring concrete is an important factor, which directly affects the timing and cost of construction. The case study that was investigated in this research, is a tunnel project located in Iran. Eighteen mix designs were prepared using properties such as different water-cement ratios and the use of two types of superplasticizer with different dosages. The optimal mix designs among the samples were separately specified.
Concrete mix designs with different curing ages were made to specify the minimum curing time in which the concrete could gain the required compressive strength. Moreover, the concrete’s compressive strength was measured for different ages in order to determine the minimum time interval. For a better insight, two mathematical equations were derived to estimate the minimum curing time and time interval. Finally, a statistical analysis was conducted in order to determine the proper time intervals. Moreover, the analysis specified the impact rate of the research parameters (i.e. the type and dosage of superplasticizer, curing time, and water-cement ratio) on the compressive strength
</abstract>

Construction Management by Controlling the Design and Curing Time of a Concrete Mix

<abstract><title style='display:none'>Abstract</title> Engineering properties such as compaction, unconfined compressive strength, consistency limits, percentage swell, free swell index, the California bearing ratio and the consolidation of bentonite stabilized with lime and phosphogypsum are presented in this paper. The content of the lime and phosphogypsum varied from 0 to 10 %. The results reveal that the dry unit weight and optimum moisture content of bentonite + 8 % lime increased with the addition of 8 % phosphogypsum. The percentage of swell increased and the free swell index decreased with the addition of 8 % phosphogypsum to the bentonite + 8 % lime mix. The unconfined compressive strength of the bentonite + 8 % lime increased with the addition of 8 % phosphogypsum as well as an increase in the curing period up to 14 days. The liquid limit and plastic limit of the bentonite + 8 % lime increased, whereas the plasticity index remained constant with the addition of 8 % phosphogypsum. The California bearing ratio, modulus of subgrade reaction, and secant modulus increased for the bentonite stabilized with lime and phosphogypsum. The coefficient of the consolidation of the bentonite increased with the addition of 8 % lime and no change with the addition of 8 % phosphogypsum.</abstract>

Department of Civil Engineering, National Institute of Technology, Hamirpur – 177005, Himachal Pradesh, India

Department of Civil Engineering, National Institute of Technology, Hamirpur - 177005, Himachal Pradesh, India

Engineering Properties of Bentonite Stabilized with Lime and Phosphogypsum

<abstract><title style='display:none'>Abstract</title>A detailed analysis of concrete structures requires knowledge of the mechanical properties of the materials used. In the case of a non-linear analysis, the scope of the information needed is even greater. In particular, the tensile strength and fracture-mechanical parameters are required for the concrete. Prospective approaches that could increase the informative value of detailed analyses include the use of stochastic modelling. It particularly enables the definition of the effects of individual input parameters on the load capacity, failure mode, and general behaviour of the structure. The presented paper aims at a detailed analysis of a reinforced-concrete beam without shear reinforcement, which is based on a complex set of laboratory tests and non-linear analyses with a sensitivity study. The laboratory program includes different types of laboratory tests. Selected and missing material parameters of the concrete are calculated according to recommendations in scientific papers and the valid standards. The results are compared and discussed.</abstract>

Non-Linear Analysis of an RC Beam Without Shear Reinforcement with a Sensitivity Study of the Material Properties of Concrete

<abstract><title style='display:none'>Abstract</title>In the 21st century, global climate change and the high level of fossil energy consumption have introduced changes affecting all sectors of the economy, including the building industry. Reducing energy consumption has become an important task for engineers because 30% of the total energy consumption is used for heating our buildings. Recycling the huge amount of industrial and agricultural by-products has also become urgent because due to their CO2 emissions, their combustion is not a state-of-the-art alternative. Besides rediscovering some long-known, nature-based insulating materials, there are also several research projects that have resulted in new products. In the last century it was relatively easy to review this product range, but nowadays there are so many kinds of nature-based thermal insulating products, there is a need for systematization, and more in-depth knowledge about them is required. The purpose of this paper is to develop a new systematization of nature-based thermal insulation materials, summarize the main knowledge about them, and indicate the direction of recent research and development.</abstract>

Nature-Based Thermal Insulation Materials From Renewable Resources – A State-Of-The-Art Review

<abstract><title style='display:none'>Abstract</title>Climate variability, particularly, that of the annual air temperature and precipitation, has received a great deal of attention worldwide. The magnitude of the variability of the factors changes according to the locations. The present study focuses on detecting the trends and variability in the annual temperature and rainfall for the district of Mandi in Himachal Pradesh, India. This study used annual and monsoon time series data for the time period 1981-2010 and modified the Mann-Kendall test and Sen's slope estimator in analyzing the problem. The results of the analysis indicate that the annual maximum temperature (TMX) and annual minimum temperature (TMN) for the period of 30 years have shown an increasing trend, whereas the monsoon’s maximum and minimum temperatures have shown a decreasing trend, although it is statistically not significant. The amount of annual rainfall does not show any significant trend, but the monsoonal rainfall has shown an increasing trend that is also statistically not significant. The resulting Mann-Kendall test statistic (Z) and Sen’s slope estimate (Q) of all the parameters studied indicate that changes are occurring in the magnitude and timing of the precipitation and temperature events at the Mandi station.</abstract>

Assessment of Trends and Variability of Rainfall and Temperature for the District of Mandi in Himachal Pradesh, India

<abstract><title style='display:none'>Abstract</title>The paper presents an analysis of changes in the structure of the average annual discharges, average annual air temperature, and average annual precipitation time series in Slovakia. Three time series with lengths of observation from 1961 to 2006 were analyzed. An introduction to spectral analysis with Fourier analysis (FA) is given. This method is used to determine significant periods of a time series. Later in this article a description of a wavelet transform (WT) is reviewed. This method is able to work with non-stationary time series and detect when significant periods are presented. Subsequently, models for the detection of potential changes in the structure of the time series analyzed were created with the aim of capturing changes in the cyclical components and the multiannual variability of the time series selected for Slovakia. Finally, some of the comparisons of the time series analyzed are discussed. The aim of the paper is to show the advantages of time series analysis using WT compared with FT. The results were processed in the R software environment.</abstract>

Advantages Of A Time Series Analysis Using Wavelet Transform As Compared With A Fourier Analysis

<abstract><title style='display:none'>Abstract</title>The article presents the results of a study of the properties of flax straw as a raw material and as a lightweight, environmentally-friendly insulation made of a two-component mixture of flax straw and liquid glass. The flax is considered to be renewable and is a 100% natural waste product of the agriculture industry, which may be widely used as sustainable building insulation after light modifications. The ratio mixes of the two-component eco-insulation of flax straw and liquid glass (Na2O(SiO2)) have been developed in terms of sustainability principles such as environmental friendliness and energy efficiency. We used thermal analysis to compare flax straw as a raw material, and a complex insulation made of flax straw demonstrated a slower decomposition of the composite and shorter peaks, which supports the concept of the transformation of flax straw with liquid glass to increase its fire resistance properties. The peaks of the loss of mass with the exothermal process were defined for both flax samples. The thermal conductivity coefficient of the material is around 0.085 W/m K, which permits its use as an effective insulation material for sustainable buildings.</abstract>

Study of Thermal Properties of Lightweight Insulation Made of Flax Straw

Instruction for Authors

Slovak Journal of Civil Engineering

The Journal of Slovak University of Technology

 The Slovak Journal of Civil Engineering (SJCE) is an international scientific journal published by the Faculty of Civil Engineering of...

Impact Factor

Five Year Impact Factor

MNiSW

Google Scholar h5-index

Google Scholar h5-median

The Slovak Journal of Civil Engineering (SJCE) is an international scientific journal published by the <a...

Slovak Journal of Civil Engineering

The Journal of Slovak University of Technology

Todos los volúmenes y ediciones en esta revista